WELLINGTON, New Zealand — Countries that manage Antarctica plan tough new controls on ships visiting the southern oceans and the fuels they use to reduce the threat of human and environmental disasters as tourist numbers rise, officials said Saturday.

The new code will reduce the number of ships carrying tourists into the region by requiring that all vessels have hulls strengthened to withstand sea ice. Officials and ship operators said a ban on heavy fuel oil will effectively shut out big cruise ships.

Experts from among the 47 signatory nations to the Antarctic Treaty — the world's main tool for managing the continent — and the International Maritime Organization discussed plans to impose a mandatory Polar Code to control all shipping in the region at a meeting in the New Zealand capital, Wellington.

Limiting accidentsThe safeguards are seen as necessary to limit accidents in the region, where blinding sleet, fog, high winds and treacherous seas pose major dangers for ships and huge problems for rescuers located thousands of miles from remote Antarctic waters.

The nearly completed Polar Code is expected to be in place by 2013, he said. Once approved, it would operate on a voluntary basis until it is ratified by treaty states and becomes legally binding.

While existing rules bar tourists or tour operators from leaving anything behind — like garbage or human waste — and require protection of animal breeding grounds, there are no formal codes on the kind of vessels that can use the waters or the kinds of fuel and other oil products they can carry.

In March, the International Maritime Organization, the United Nations' shipping agency, is to ratify a ban on the carriage or use of heavy fuel oil in Antarctica. It is to come into effect in 2011.

Spike in tourist trafficThe moves follow a huge growth in tourist traffic as people flock to see the world's last great wilderness.

Annual tourist numbers have grown from about 10,000 a decade ago to 45,000 last year. Tourists can pay between $3,000 and $24,000 for a two-week trip. Some travel on ships carrying up to 3,000 passengers that also take many tons of heavy fuel oil, chemicals and garbage that can pollute the region.

Nathan Russ, operations manager of Antarctic eco-tourism company Heritage Expeditions, said the proposed heavy fuel ban "will most likely regulate the biggest cruise ships out of Antarctic operations" because of the costs involved in switching to lighter fuel.

The Antarctic Treaty, first signed in 1959, is the main tool for regulating what is the world's only continent without a native human population. New Zealand is one of the dozen founding members of the treaty, along with the United States, Russia and Britain. The treaty now has 47 signatories.